FIELD OF THE INVENTION
The present invention relates to an endoscope apparatus provided with means for detecting in advance whether or not an insertion aid is loose.
In recent years, medical endoscopes of the type whose elongated inserting section can be inserted into a living body so as to make a diagnosis have been widely used. In addition, industrial endoscopes have been widely used of the type whose elongated inserting section is inserted into a tube of a boiler, a turbine or the like to inspect the interior thereof.
In general, such an industrial endoscope is applied to various portions each having a different size, and if the inner diameter of the inserting end portion of the endoscope greatly differs from the inner diameter of a portion into which it is inserted, the inserting section of the endoscope apparatus greatly fluctuates within the portion into which it has been inserted. As a result, the direction of observation is difficult to fix exactly. Also, if the outer diameter of the inserting end portion is larger than the diameter of the portion into which it is inserted, the inserting end portion may be inclined downwardly in that portion. As a result, a bottom wall of the portion may only be observed.
To solve the above-described problems, the present applicant proposed endoscope apparatus of the type whose endoscope is provided with an insertion aid.
In the conventional example shown in, for example, Japanese Patent Laid-open No. 26923/1985, means for attaching an insertion aid to an inserting section, a member of an insertion aid is fixed in the inserting section of an endoscope by press fitting.
U.S. Pat. No. 4,676,230 (Japanese Patent Laid-open No. 183615/1986) and Japanese Utility Model Laid-open No. 33021/1987 propose endoscope apparatus of the type in which the aforementioned attaching means is such that a member of an insertion aid is engaged with a threaded portion which is formed around the leading end portion of an endoscope, the attaching means further having the function of preventing the insertion aid from coming off by forming a projection in the circumferential direction.
The former one of the above-described conventional examples has the disadvantage that since it is difficult to positively fix the insertion aid, the insertion aid tends to easily come off. In addition, it is difficult to detect in advance whether or not the state of attachment of the insertion aid is loose.
The latter conventional example has the disadvantage that, although a mechanism for preventing an insertion aid from coming off is provided, even if the insertion aid is loose, it is difficult for an endoscope operator to detect that fact.
Should the insertion aid come off in a boiler, an engine or the like, it will be difficult to eliminate the insertion aid to the exterior. In addition, if the insertion aid which has come off is left there, the boiler, the engine or the like may fail, thus resulting in serious accidents.